mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
43 lines
1.4 KiB
Solidity
43 lines
1.4 KiB
Solidity
==== ExternalSource: _prbmath/PRBMathCommon.sol ====
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==== ExternalSource: _prbmath/PRBMathSD59x18.sol ====
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==== Source: ramanujan_pi.sol ====
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import "_prbmath/PRBMathSD59x18.sol";
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// The goal of this test file is to implement Ramanujan's pi approximation using various libraries.
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function factorial(uint n) pure returns (uint ret) {
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ret = 1;
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for (; n > 1; --n)
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ret *= n;
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}
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contract test {
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using PRBMathSD59x18 for int256;
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function prb_scale(uint n) internal pure returns (int256 ret) {
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// Scale to SD59x18
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ret = int256(n * 10e17);
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}
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// This dumb implementation of Ramanujan series calculates 1/pi
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function prb_pi() external pure returns (int256 ret) {
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uint n = 6; // More than 6 iterations results in failure
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for (uint k = 0; k < n; k++) {
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int256 a = prb_scale(factorial(4 * k)).div(prb_scale(factorial(k)).pow(4));
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int256 b = (prb_scale(25390).mul(prb_scale(k)) + prb_scale(1103)).div(prb_scale(396).pow(4 * k));
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ret += a.mul(b);
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}
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ret = ret.mul(prb_scale(2).sqrt().mul(prb_scale(2)).div(prb_scale(99).pow(2)));
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ret = prb_scale(1).div(ret);
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}
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}
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// ----
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// constructor()
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// gas irOptimized: 430305
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// gas legacy: 649335
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// gas legacyOptimized: 473132
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// prb_pi() -> 3141592656369545286
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// gas irOptimized: 57478
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// gas legacy: 103112
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// gas legacyOptimized: 75735
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